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- Regulatory practices on the genotoxicity testing of nanomaterials and outlook for the futurePublication . Andreoli, Cristina; Dusinska, Maria; Bossa, Cecilia; Battistelli, Chiara Laura; Silva, Maria João; Louro, HenriquetaHighlights: - Genotoxicity testing of chemicals requires multiple tests to cover key endpoints; - NMs have distinct properties that require adaptations of conventional testing; - Approaches for genotoxicity testing of the NMs reviewed show challenges; - The level of harmonization between different frameworks is debated; - New approach methodologies are underlined to support NMs'regulation.
- Toward harmonizing protein data in food composition databases: evaluating perspectives, methods and implicationsPublication . Pferdmenges, Larissa E.; Colombani, Paolo C.; Carlsen, Monica Hauger; Pajari, Anne-Maria; Poulsen, Anders; Dias, Maria da Graça; Moller, Anders; Lisciani, Silvia; Wust, Matthias; Bonsmann, Stefan; Schweiggert-Weisz, UteProtein content in foods has historically been estimated by multiplying measured nitrogen content with a universal nitrogen-to-protein conversion factor (NCF) of 6.25. Despite scientific consensus that this approach leads to systematic overestimations due to variations in amino acid composition and non-protein nitrogen (NPN) content, no universally accepted revision has been implemented. This review critically examines diverse perspectives on protein quantification and their implications for Food Composition Databases (FCDBs). A structured definition of protein for FCDBs is proposed, including amino acid residues, free amino acids and small peptides, while explicitly excluding NPN and prosthetic groups. Furthermore, analytical methods and NCF calculations are evaluated in order to provide more accurate assessments of protein content across a range of food matrices. The review highlights the importance of selecting food-specific NCFs to reduce overestimations, ensuring both scientific accuracy and practical feasibility. By addressing methodological shortcomings and proposing a refined protein quantification framework, this work aims to facilitate the transition toward more precise and harmonized protein values in FCDBs, benefiting nutritional research, dietary guidelines, and food labeling regulations.
- Biocompatibility testing and antioxidant properties of cerium dioxide nanoparticles in human nervous system cellsPublication . Fernández-Bertólez, Natalia; Touzani, Assia; Ramos-Pan, Lucía; Reis, Ana Teresa; Teixeira, João Paulo; Laffon, Blanca; Valdiglesias, VanessaCerium dioxide nanoparticles (CeO NP), or nanoceria, are versatile materials with interesting properties for industry and medicine fields, particularly redox properties and catalytic activity. Because of their distinctive features, they have gained high attention in biomedical and pharmacological research to be employed in drug delivery, tissue regeneration, radioprotection, or diagnostic imaging. However, previous works reported that nanoceria may also induce reactive oxygen species (ROS) under certain conditions, leading to cellular stress, cellular damage, or cell death. In this study, the effects of CeO NP on cell viability and morphology as well as their influence on oxidative stress (both oxidant and ROS scavenging capacities) were investigated in nervous system cells (SH-SY5Y neuronal and A172 glial cells) treated with a wide range of CeO NP concentrations (1-100 µg/mL) for several treatment times. Results obtained showed that, despite being stable in time and effectively internalized by both cell types, CeO NP did not produce significant decrease in viability, evaluated by MTT assay, morphological alterations, or intrinsic cell-free ROS, but they generated cellular ROS limited to longer exposure periods. Furthermore, CeO NP demonstrated a certain intrinsic ability to scavenge ROS generated by HO in both tested cell types, more pronounced in neuronal cells. These results confirm the good biocompatibility of nanoceria on human nervous system cells and support further exploring their potential use in biomedicine field, particularly for those therapeutic and diagnostic applications related to the nervous system.
- Translational activation of Δ160p53 is triggered during the Integrated Stress Response to promote survivalPublication . Ramalho, Ana Catarina; López-Iniesta, Maria José; Lacerda, Rafaela; Parkar, Shrutee N.; Romão, Luísa; Candeias, Marco M.The p53 gene was discovered 45 years ago, but to this day some aspects of its regulation and function remain a mystery. This gene encodes for a group of protein isoforms that display different functions, acting cooperatively in stress response. Full-length p53 (FLp53), the best studied isoform, is a transcription factor with targets across several pathways, promoting cellular adaption during stress. Classical roles of FLp53 are the induction of cell cycle arrest and, a as a last resort, apoptosis. The short isoform Δ160p53 is an oncoprotein commonly overexpressed in tumours that can be translated from the same mRNA as FLp531. The exact mechanisms and factors that regulate Δ160p53 translation and how it exerts its pro-survival functions remain unexplored. In this work, it was demonstrated that the translation of Δ160p53 is mediated by an Internal Ribosome Entry Site (IRES) and its expression is induced by the Integrated Stress Response (ISR). Additionally, a mass spectrometry analysis uncovered potential new RNA-binding proteins involved in the translation of Δ160p53, and it was verified that translation factors specifically associated with alternative modes of initiation during the ISR promoted the translation of Δ160p53. In parallel, Δ160p53 was found to interact with FLp53 and modulate its transcriptional activity to favour a pro-survival response to stress. While suppressing genes involved in cell cycle arrest (CDKN1A) and apoptosis (PUMA), Δ160p53 enhances the expression of genes involved in cellular metabolism and protection against ferroptosis: SESN1, SESN2 and SLC7A11. Furthermore, Δ160p53 was shown to suppress ferroptosis and to interact with the SLC7A11 promoter. This study has uncovered new modes of p53 regulation and hints at a physiological role for Δ160p53 in the context of the ISR. However, abnormal levels of Δ160p53 may contribute to an exacerbated pro-survival p53 target signature, demonstrating the importance of p53 isoform balance.
- Comunicação em composição e segurança dos alimentos na perspetiva do INSAPublication . Brazão, RobertoApresentação sobre a importância da comunicação em composição de alimentos e em segurança dos alimentos na perspectiva do INSA. Enquadramento, metodologia e exemplos.